Great device for first time vape users. Battery life more than adequate for our usage. Bubbler instructional video could use some improvement. At least for my device, even after coming up to temperature, insertion of the bubbler requires sufficient pressure for bubbler to engage chamber with a slight click. Failure to do this seems to create some sort of air leakage, which in turn results in serious coughing. Ensuring a click upon engagement eliminates the coughing. The video makes it appear as though one need only set the bubbler in the chamber. This doesn’t work for me at all. Gotta engage it until the “click”.